function copyToClipboard(txt) { 
			if(window.clipboardData) { 
				window.clipboardData.clearData(); 
				window.clipboardData.setData("Text", txt); 
			} else if(navigator.userAgent.indexOf("Opera") != -1) { 
				window.location = txt; 
			} else if (window.netscape) { 
				try { 
					netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect"); 
				} catch (e) { 
					alert("您的firefox安全限制限制您进行剪贴板操作，请打开'about:config'将'signed.applets.codebase_principal_support'设置为true之后重试"); 
					return false; 
				} 
				var clip = Components.classes["@mozilla.org/widget/clipboard;1"].createInstance(Components.interfaces.nsIClipboard); 
				if (!clip) 
				return; 
				var trans = Components.classes["@mozilla.org/widget/transferable;1"].createInstance(Components.interfaces.nsITransferable); 
				if (!trans) 
				return; 
				trans.addDataFlavor("text/unicode"); 
				var str = new Object(); 
				var len = new Object(); 
				var str = Components.classes["@mozilla.org/supports-string;1"].createInstance(Components.interfaces.nsISupportsString); 
				var copytext = txt; 
				str.data = copytext; 
				trans.setTransferData("text/unicode",str,copytext.length*2); 
				var clipid = Components.interfaces.nsIClipboard; 
				if (!clip) 
				return false; 
				clip.setData(trans,null,clipid.kGlobalClipboard);
			} 
}